Problem Statement: In order to obtain energy independence from conventional sources, there is a significant interest in the production of biogas and “green energy” during wastewater treatment. Due to increased emphasis on sustainability and potential for additional revenue streams, utilities are expected to adopt energy production from digester gas in the near future. Although biogas from treatment plants provides a good source of energy,the cost and efficiency of the energy production is limited by various impurities. Among the key impurities in the digester gas are siloxanes. Nearly 10% of siloxanes entering the treatment plant ends up in the sludge (and hence, potentially into the anaerobic digesters). In the digester, the siloxane volatilizes and becomes part of the biogas. During the combustion of biogas (for energy production), siloxanes become abrasive microcrystalline silica particles and cause severe damage to gas engines, heat exchangers, catalytic and exhaust gas treatment systems. The damaged caused results in high cost and regular maintenance or repair/replacement of equipment. Hence, it is essential that a pre-treatment technology be developed that can remove siloxanes efficiently and economically for biogas green energy production from wastewater treatment facilities and landfills.
Technology Description: NEI Corporation, in conjunction with our collaborator Kennedy Jenks whose expertise is in environmental solutions, proposes to develop a Nanomaterials-based drop-in technology that will significantly enhance the capacity of activated carbon to remove siloxane from digester and landfill biogas. In addition, the higher selectivity and ability to regenerate the media will render energy production from biogas more cost effective. The material developed will be environmentally benign and economical. The proposed project builds upon NEI Corporation’s and its collaborators’ efforts in the area of using Nanoscale materials to remove contaminants from gas and liquid streams. Anticipated Benefits: With an emerging thrust to generate green energy and potential for increase revenue source as well as minimized green house gas emissions, more wastewater utilities that already have anaerobic digesters are likely to adopt biogas energy production. Due to ubiquitous presence of siloxa ne in wastewaters, almost all of these utilities will require a pretreatment technology to selectively remove siloxanes. Also many industries generating high strength organic wastewaters (e.g., diary, food processing facilities) have the potential to generate biogas for energy from their waste streams; these facilities will also benefit from a technology to effectively remove siloxane. The proposed approach is expected to offer a cost-effective means for removal of siloxanes from biogas.